1. HVAC EQUIPMENT General
The prevailing temperature and humidity condition of a space is a result of the balance between the heat entering a building and exiting it. Regulation of these heat transfers requires the introduction of heating and cooling systems in a building.

2. HVAC EQUIPMENT Systems overview (additional information)
HVAC systems have the following elements in common:
Equipment to generate heating or cooling: The equipment is selected with a capacity to offset the peak load of the space or spaces to be served.
A means of distributing heat, cooling, and/or filtered ventilation air where needed: air, water, or steam.
Devices that deliver the heat, cooling, and/or fresh air into the building: registers and diffusers, hydronic radiators or convectors, and fan coil units.
All these above functions are sometimes combined into a single unit that by itself converts an energy source into heating or cooling and delivers it to the space.

3. HEATING EQUIPMENT Central heat sources
Selection: Selection of equipment depends on economic factors once the total required capacity has been calculated. The choice of components depends on the types of fuel available and availability of space and structural support.

4. COMBUSTION/ELECTRIC HEATING
Furnace (see section 16.0)
Efficiency of a furnace = heat delivered/energy input.
Boiler (see section 16.0)
Efficiency of a boiler = heat delivered/energy input.
Heat pump (see sections 16.0 & 16.5)
Efficiency of a heat pump [when in heating mode is measured in COP or HSPF (Heating Season Performance Factor)]